This invention pertains to the field of microbial polysaccharides. In particular, the polysaccharides of interest occur in the form of exocellular heteropolysaccharides which are high molecular weight, generally linear or branched, carbohydrates containing two or more different kinds of monosaccharides that form repeating units that are polymerized.
These heteropolysaccharides are widely used in agriculture and a variety of industrial applications, including food, well drilling, paint, etc. Commercial demand for these heteropolysaccharides continues to increase.
One of the most widely used heteropolysaccharides is xanthan, or xanthan gum, which is produced during fermentation by bacteria of the genus Xanthomonas, typically Xanthomonas campestris. This xanthan heteropolysaccharide contain glucose, mannose and glucuronic acid. Various industrial uses of xanthan gum are known, see e.g. U.S. Pat. Nos. 3,326,305, and 4,244,826.
Another widely useful class of heteropolysaccharides are the succinoglycans, a class of exocellular heteropolysaccharides produced by bacteria of the genera Alcaligenes, Agrobacterium and Pseudomonas. These succinoglycans contain galactose, glucose and variable proportions of acid residues such as pyruvate, succinate and acetate. Industrial uses for these succinoglycans are also known, see e.g., European Patent Office Application No. 040445, and U.S. Pat. Nos. 4,339,239, 4,347,289, and 4,298,795.